Why antimatter matters

ANTIMATTER has been around since the big bang 13.7 billion years ago, when theories say it was born in equal amounts as matter. But that equality no longer holds true, and ever since humans have been aware of antimatter, they have wondered why.

English physicist Paul Dirac came up with the idea of antimatter 79 years ago as he tried to reconcile quantum theory with special relativity. Dirac argued on theoretical grounds that antimatter had to exist. Detection of the positron in 1932 confirmed his theory. In this way, the positron was the first particle to be born out of pure thought, marking "perhaps the biggest jump of all the big jumps" of the 20th century, according to Werner Heisenberg, pioneer of quantum mechanics.

Now physicists have managed to create and trap antihydrogen atoms (see "Antihydrogen trapped at long last"). Studies of these newly ensnared anti-atoms will fire up the imaginations of Dirac's successors as they struggle to understand why antimatter is so rare. By the time we reach 2031, the centenary of Dirac's insight, perhaps we will have solved one of the great cosmic mysteries: where all that antimatter went, and why.

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